The goal of this RCA is to further the investigation and development of techniques for the investigation of the genetic basis of alcohol dependence. Short-term studies are designed to address the role of protein phosphorylation in regulating sensitivity and neuroadaptive processes. Protein phosphorylation is a basic regulator of cellular processes. One gene family the calcium/lipid activated protein kinase C (PKC) encodes at least 11 isotypes. Among these isotypes, the y-PKC isotype, is the only PKC solely expressed in neurons of the brain and spinal cord. Until the creation of null mutant mice ("knock-outs") that carry a disrupted y-PKC gene, it has been difficult to analyze the role of specific isotypes in behavioral, biochemical, and physiological processes. Y-PKC null mutants differ in their responses to ethanol but these responses are mediated by polygenic systems and it is unknown whether the impact of the null mutation in y-PKC is influenced by genetic background and varying gene-gene interactions. The goal of this proposal is to investigate the question of epistatic interactions by introgressing the null y-PKC or wild-type on to a variety of inbred strains which are known to differ in their responses to ethanol to create congenic lines. These backgrounds include: C57/BL6J, DBA/2J, and 129/Svev. Initial sensitivity to ethanol, the development of ethanol tolerance, and drinking of ethanol will be examined in these congenic lines as well as ligand-gated ion channel function. Long-term studies are designed to establish the molecular technique of RNA differential display to be used to address the functional nature of neuroadaptive processes that underlie tolerance development to ethanol and the lack of such tolerance in y-PKC null mutants.